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1. Field of the Invention
The present invention relates to lifting apparatus and accessories, and more particularly to an improved spreader bar lifting apparatus for use with cranes and other lifting devices that use slings. Even more particularly the present invention relates to an improved spreader bar arrangement that includes a main beam or bar that supports a flexible member preferably comprised of a plurality of links or sections, and wherein the links or sections have connectors that enable connections to be made between the links and a load to be lifted or load lines (eg. slings).
2. General Background of the Invention
Spreader bars are commonly used in industry for lifting large objects with a single hook that is attached to the crown block and lift cables of a crane. A lifting hook is commonly provided with a pair of slings that depend from the crane hook at angles in a bridle fashion, each of the slings connecting to an end portion of the spreader bar. Parallel, depending lift lines are then suspended from the end portions of the spreader bar downwardly to the load that is to be lifted.
One of the problems with spreader bars is that of sizing the spreader bar to meet a particular load. Loads typically differ in size and in configuration. Some devices have been patented that enable the overall length of the bar to be changed by changing the center section to which a pair of end caps attach. An example of such as a spreader bar that has been patented can be seen in my prior U.S. Pat. No. 4,397,493, and entitled xe2x80x9cSpreader Bar Assemblyxe2x80x9d. Other spreader bar patents include U.S. Pat. Nos. 4,538,849 and 5,863,085, each incorporated herein by reference.
In some situations, a user has a pair of cranes or like lifting devices such as for example a ship having two cranes positioned at opposite ends of an opening in the hull above a hold or other cargo area. This presents a problem to the ship operator when very heavy loads of differing configurations are to be lifted out of the cargo area. Sometimes the position of the load in the cargo area requires that a crane be positioned at such an angle of inclination that the lifting capacity of the boom is at its lowest portion of its range.
The present invention provides an improved spreader bar apparatus that includes a pair of bar sections. The present invention provides an improved spreader bar apparatus that includes a bar or beam member having first and second end portions. Each of the end portions provides a lifting portion that can be attached to a lifting device such as a crane. A flexible member is supported by each of the bar members at the lifting portions, the flexible member preferably extending in a curved fashion below the bar and in between the two bar ends.
The flexible member provides attachments at spaced apart intervals along the flexible member, each of the attachments being a location that can support a lifting line, sling or the like.
The flexible member is preferably comprised of a plurality of links connected together end to end.
The flexible member can be comprised of a plurality of links that are pinned together.
The flexible member can be comprised of a plurality of plate members, each plate member being an elongated structure having end portions, wherein one end portion of one plate member is connected to an end portion of another plate member, preferably using a pinned connection. At that pinned connection, a third plate member can be positioned to extend downwardly from the pinned connection and assume a generally vertical position. This third plate member functions as a load carrying member to which a depending lift line, sling or the like can be attached (for example, using shackles).
The plurality of plate members thus includes a first plurality of laterally extending plate members and a second plurality of vertically extending plate members. In one embodiment, the apparatus includes two separate lifting cranes positioned at spaced apart locations, each of the lifting cranes supporting a separate end of the bar.